1. Field of Invention
The present invention relates to color filter substrates suitable for use in liquid crystal display devices for electronic apparatuses, such as mobile phones and mobile personal computers. The present invention also relates to methods for manufacturing such color filter substrates. The present invention also relates to liquid crystal display devices and electro-optical devices including the color filter substrates and to methods for manufacturing the electro-optical devices.
More particularly, the present invention relates to a color filter substrate, in which a plurality of color pixels, such as R (red), G (green), and B (blue) pixels, or C (cyan), M (magenta), and Y (yellow) pixels, are formed in a predetermined region on a base member delimited by a bank-like delimiting member, and a protective layer is formed on the surfaces of the color pixels, to a method for manufacturing the color filter substrate, to a liquid crystal display device, to an electro-optical device, and to a method for manufacturing the electro-optical device.
2. Description of Related Art
Recently, liquid crystal display devices have been widely used for electronic apparatuses, such as mobile phones and mobile personal computers. Liquid crystal display devices in which color displays are performed using color filter substrates have also been widely used.
In a conventional color filter substrate, such as the one shown in FIG. 18, on the surface of a base member 201 composed of glass, plastic, or the like, for example, color pixels 202R, 202G, and 202B of R (red), G (green), and B (blue), respectively, are arranged in a predetermined pattern, such as a stripe pattern, a mosaic pattern, or a delta pattern, and a protective layer 203 is further formed thereon.
The protective layer 203 is formed in order to perform the following four functions. Firstly, by forming the protective layer 203, the surface of the color filter substrate is planarized, and thereby, when electrodes are formed on the surface of the color filter substrate, the function of preventing the disconnection of the electrodes is performed.
Secondly, the protective layer 203 is formed so that the function of improving the contrast ratio between pixels is performed by reducing resistance of the electrodes on the protective layer 203. Thirdly, the protective layer 203 is formed in order to prevent the pixels included in the color filter from being flawed in the steps subsequent to the formation of the protective layer 203, that is, in order to perform the protective function.
Fourthly, when the color filter substrate is used for a liquid crystal display device, by forming the protective layer 203, it is possible to prevent impurities from being diffused from the color filter substrate into the liquid crystal after the liquid crystal is filled in the cell gap.
When such a protective layer 203 is formed, conventionally, in general, a black mask is formed on the base member 201, and a plurality of color pixels, such as R (red), G (green), and B (blue) pixels, or C (cyan), M (magenta), and Y (yellow) pixels, are formed in a predetermined region delimited by the black mask. A liquid transparent resist or the like is then applied over the entire surface of the base member 201 provided with the color pixels at a uniform thickness by spin-coating or the like, and the transparent resist or the like is subjected to patterning by a photolithographic method to form the protective layer 203.
However, when the photolithographic method is used, problems, such as an increase in costs, arise because the process is complex and large amounts of the individual color materials, the photoresist, etc. are consumed. In order to overcome such problems, a method has been proposed in which a filament or the like is arranged in a dot pattern by ejecting materials for the filter or the like in a dot pattern by an ink-jet method.
That is, as shown in FIG. 19(a), first, a bank-like delimiting member 5 is formed on a glass base member 12 at a predetermined height. The delimiting member 5 is composed of a resinous material which has repellency to materials 13 for the filter (see FIG. 19(b)) ejected by the ink-jet method. Therefore, as shown in FIG. 19(b), when the filament or the like is formed by supplying the materials 13 for the filter to the individual regions, it is possible to prevent the adjacent materials 13 for the filter to be mixed with each other.
In this way, as shown in FIG. 19(c), the filament or the like composed of the color pixels 3R, 3G, and 3B having different colors is formed. Furthermore, as shown in FIG. 19(d), a protective layer 4 is applied on the color pixels 3R, 3G, and 3B, and the color filter substrate is thereby manufactured.